Who needs such accoutrements as a torso, limbs, eyes and ears? To capture the oppressive nature of memory and human consciousness, actress Nanna Ingvarsson needs just her mouth. Ingvarsson is the only visible figure in “The Beckett Trio,” an aptly intense showcase of three bleak, minimalist Samuel Beckett playlets directed by Robert McNamara for Scena Theatre. In the second playlet, “Not I,” the actress depicts the protagonist: a disembodied mouth hovering midair, amid darkness.

The Mouth reels off recollections of speech and silence, speaking so fast (Beckett wanted the delivery to be lickety-split) that you sometimes strain to understand. Occasionally, an image surges up from the verbal current: cowslips, a ray of light, a shopping bag, a buzzing sound. Periodically, the Mouth seems to hear an interruption — “What?” she squawks — and sometimes she editorializes with a scoffing laugh. (As the consciousness-burdened figures in these three plays usually do, she seems to be describing herself in the third person.)

Over the course of the brief piece, Ingvarsson is hidden behind a dark wall, with an aperture revealing her frenetically moving mouth. It’s a tour de force by the actress, who generates welcome bursts of humor with her squawks and scoffs, even as her agitated speech evokes a disquieting vision of awareness.

“Not I” epitomizes Beckett’s preference for paring away theater’s dispensable aspects. The other two playlets are nearly as austere. “Footfalls” imagines a woman who shares a suffocating life with her bedridden mother. A haggard figure in a long, gray skirt and shawl, with straggling white hair and a numb expression, Ingvarsson’s May paces back and forth in front of a grimy wall. Occasionally, the disembodied voice of her mother (an entrancingly eerie Nancy Robinette) is heard, narrating her daughter’s movement, for instance. When May speaks — offering her mother an injection, remembering a stint of nocturnal pacing at a church — the words can be so unemotional that the syllables barely hold together, as if language itself were disintegrating.

Replete with incantatory repetition, the third playlet, “Rockaby,” also summons a vision of stoicism amid monotony. We see Ingvarsson’s Woman, wearing a beaded black dress and hat, rocking in a rocking chair. Meanwhile, her chanting voice, in voice-over, recalls a lonely, restless figure gravitating to a window. When the voice-over pauses, the visible Woman cries out, “More!” It’s a glimpse of someone dying — or maybe someone living. After all, they’re the same thing.